Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/dccp/minisocks.c
4 *
5 * An implementation of the DCCP protocol
6 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
7 */
8
9#include <linux/dccp.h>
10#include <linux/gfp.h>
11#include <linux/kernel.h>
12#include <linux/skbuff.h>
13#include <linux/timer.h>
14
15#include <net/sock.h>
16#include <net/xfrm.h>
17#include <net/inet_timewait_sock.h>
18
19#include "ackvec.h"
20#include "ccid.h"
21#include "dccp.h"
22#include "feat.h"
23
24struct inet_timewait_death_row dccp_death_row = {
25 .sysctl_max_tw_buckets = NR_FILE * 2,
26 .hashinfo = &dccp_hashinfo,
27};
28
29EXPORT_SYMBOL_GPL(dccp_death_row);
30
31void dccp_time_wait(struct sock *sk, int state, int timeo)
32{
33 struct inet_timewait_sock *tw;
34
35 tw = inet_twsk_alloc(sk, &dccp_death_row, state);
36
37 if (tw != NULL) {
38 const struct inet_connection_sock *icsk = inet_csk(sk);
39 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
40#if IS_ENABLED(CONFIG_IPV6)
41 if (tw->tw_family == PF_INET6) {
42 tw->tw_v6_daddr = sk->sk_v6_daddr;
43 tw->tw_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
44 tw->tw_ipv6only = sk->sk_ipv6only;
45 }
46#endif
47
48 /* Get the TIME_WAIT timeout firing. */
49 if (timeo < rto)
50 timeo = rto;
51
52 if (state == DCCP_TIME_WAIT)
53 timeo = DCCP_TIMEWAIT_LEN;
54
55 /* tw_timer is pinned, so we need to make sure BH are disabled
56 * in following section, otherwise timer handler could run before
57 * we complete the initialization.
58 */
59 local_bh_disable();
60 inet_twsk_schedule(tw, timeo);
61 /* Linkage updates.
62 * Note that access to tw after this point is illegal.
63 */
64 inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
65 local_bh_enable();
66 } else {
67 /* Sorry, if we're out of memory, just CLOSE this
68 * socket up. We've got bigger problems than
69 * non-graceful socket closings.
70 */
71 DCCP_WARN("time wait bucket table overflow\n");
72 }
73
74 dccp_done(sk);
75}
76
77struct sock *dccp_create_openreq_child(const struct sock *sk,
78 const struct request_sock *req,
79 const struct sk_buff *skb)
80{
81 /*
82 * Step 3: Process LISTEN state
83 *
84 * (* Generate a new socket and switch to that socket *)
85 * Set S := new socket for this port pair
86 */
87 struct sock *newsk = inet_csk_clone_lock(sk, req, GFP_ATOMIC);
88
89 if (newsk != NULL) {
90 struct dccp_request_sock *dreq = dccp_rsk(req);
91 struct inet_connection_sock *newicsk = inet_csk(newsk);
92 struct dccp_sock *newdp = dccp_sk(newsk);
93
94 newdp->dccps_role = DCCP_ROLE_SERVER;
95 newdp->dccps_hc_rx_ackvec = NULL;
96 newdp->dccps_service_list = NULL;
97 newdp->dccps_service = dreq->dreq_service;
98 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
99 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
100 newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
101
102 INIT_LIST_HEAD(&newdp->dccps_featneg);
103 /*
104 * Step 3: Process LISTEN state
105 *
106 * Choose S.ISS (initial seqno) or set from Init Cookies
107 * Initialize S.GAR := S.ISS
108 * Set S.ISR, S.GSR from packet (or Init Cookies)
109 *
110 * Setting AWL/AWH and SWL/SWH happens as part of the feature
111 * activation below, as these windows all depend on the local
112 * and remote Sequence Window feature values (7.5.2).
113 */
114 newdp->dccps_iss = dreq->dreq_iss;
115 newdp->dccps_gss = dreq->dreq_gss;
116 newdp->dccps_gar = newdp->dccps_iss;
117 newdp->dccps_isr = dreq->dreq_isr;
118 newdp->dccps_gsr = dreq->dreq_gsr;
119
120 /*
121 * Activate features: initialise CCIDs, sequence windows etc.
122 */
123 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
124 sk_free_unlock_clone(newsk);
125 return NULL;
126 }
127 dccp_init_xmit_timers(newsk);
128
129 __DCCP_INC_STATS(DCCP_MIB_PASSIVEOPENS);
130 }
131 return newsk;
132}
133
134EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
135
136/*
137 * Process an incoming packet for RESPOND sockets represented
138 * as an request_sock.
139 */
140struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
141 struct request_sock *req)
142{
143 struct sock *child = NULL;
144 struct dccp_request_sock *dreq = dccp_rsk(req);
145 bool own_req;
146
147 /* TCP/DCCP listeners became lockless.
148 * DCCP stores complex state in its request_sock, so we need
149 * a protection for them, now this code runs without being protected
150 * by the parent (listener) lock.
151 */
152 spin_lock_bh(&dreq->dreq_lock);
153
154 /* Check for retransmitted REQUEST */
155 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
156
157 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_gsr)) {
158 dccp_pr_debug("Retransmitted REQUEST\n");
159 dreq->dreq_gsr = DCCP_SKB_CB(skb)->dccpd_seq;
160 /*
161 * Send another RESPONSE packet
162 * To protect against Request floods, increment retrans
163 * counter (backoff, monitored by dccp_response_timer).
164 */
165 inet_rtx_syn_ack(sk, req);
166 }
167 /* Network Duplicate, discard packet */
168 goto out;
169 }
170
171 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
172
173 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
174 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
175 goto drop;
176
177 /* Invalid ACK */
178 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
179 dreq->dreq_iss, dreq->dreq_gss)) {
180 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
181 "dreq_iss=%llu, dreq_gss=%llu\n",
182 (unsigned long long)
183 DCCP_SKB_CB(skb)->dccpd_ack_seq,
184 (unsigned long long) dreq->dreq_iss,
185 (unsigned long long) dreq->dreq_gss);
186 goto drop;
187 }
188
189 if (dccp_parse_options(sk, dreq, skb))
190 goto drop;
191
192 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL,
193 req, &own_req);
194 if (child) {
195 child = inet_csk_complete_hashdance(sk, child, req, own_req);
196 goto out;
197 }
198
199 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
200drop:
201 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
202 req->rsk_ops->send_reset(sk, skb);
203
204 inet_csk_reqsk_queue_drop(sk, req);
205out:
206 spin_unlock_bh(&dreq->dreq_lock);
207 return child;
208}
209
210EXPORT_SYMBOL_GPL(dccp_check_req);
211
212/*
213 * Queue segment on the new socket if the new socket is active,
214 * otherwise we just shortcircuit this and continue with
215 * the new socket.
216 */
217int dccp_child_process(struct sock *parent, struct sock *child,
218 struct sk_buff *skb)
219{
220 int ret = 0;
221 const int state = child->sk_state;
222
223 if (!sock_owned_by_user(child)) {
224 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
225 skb->len);
226
227 /* Wakeup parent, send SIGIO */
228 if (state == DCCP_RESPOND && child->sk_state != state)
229 parent->sk_data_ready(parent);
230 } else {
231 /* Alas, it is possible again, because we do lookup
232 * in main socket hash table and lock on listening
233 * socket does not protect us more.
234 */
235 __sk_add_backlog(child, skb);
236 }
237
238 bh_unlock_sock(child);
239 sock_put(child);
240 return ret;
241}
242
243EXPORT_SYMBOL_GPL(dccp_child_process);
244
245void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
246 struct request_sock *rsk)
247{
248 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
249}
250
251EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
252
253int dccp_reqsk_init(struct request_sock *req,
254 struct dccp_sock const *dp, struct sk_buff const *skb)
255{
256 struct dccp_request_sock *dreq = dccp_rsk(req);
257
258 spin_lock_init(&dreq->dreq_lock);
259 inet_rsk(req)->ir_rmt_port = dccp_hdr(skb)->dccph_sport;
260 inet_rsk(req)->ir_num = ntohs(dccp_hdr(skb)->dccph_dport);
261 inet_rsk(req)->acked = 0;
262 dreq->dreq_timestamp_echo = 0;
263
264 /* inherit feature negotiation options from listening socket */
265 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
266}
267
268EXPORT_SYMBOL_GPL(dccp_reqsk_init);
1/*
2 * net/dccp/minisocks.c
3 *
4 * An implementation of the DCCP protocol
5 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#include <linux/dccp.h>
14#include <linux/gfp.h>
15#include <linux/kernel.h>
16#include <linux/skbuff.h>
17#include <linux/timer.h>
18
19#include <net/sock.h>
20#include <net/xfrm.h>
21#include <net/inet_timewait_sock.h>
22
23#include "ackvec.h"
24#include "ccid.h"
25#include "dccp.h"
26#include "feat.h"
27
28struct inet_timewait_death_row dccp_death_row = {
29 .sysctl_max_tw_buckets = NR_FILE * 2,
30 .hashinfo = &dccp_hashinfo,
31};
32
33EXPORT_SYMBOL_GPL(dccp_death_row);
34
35void dccp_time_wait(struct sock *sk, int state, int timeo)
36{
37 struct inet_timewait_sock *tw;
38
39 tw = inet_twsk_alloc(sk, &dccp_death_row, state);
40
41 if (tw != NULL) {
42 const struct inet_connection_sock *icsk = inet_csk(sk);
43 const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
44#if IS_ENABLED(CONFIG_IPV6)
45 if (tw->tw_family == PF_INET6) {
46 tw->tw_v6_daddr = sk->sk_v6_daddr;
47 tw->tw_v6_rcv_saddr = sk->sk_v6_rcv_saddr;
48 tw->tw_ipv6only = sk->sk_ipv6only;
49 }
50#endif
51
52 /* Get the TIME_WAIT timeout firing. */
53 if (timeo < rto)
54 timeo = rto;
55
56 tw->tw_timeout = DCCP_TIMEWAIT_LEN;
57 if (state == DCCP_TIME_WAIT)
58 timeo = DCCP_TIMEWAIT_LEN;
59
60 /* tw_timer is pinned, so we need to make sure BH are disabled
61 * in following section, otherwise timer handler could run before
62 * we complete the initialization.
63 */
64 local_bh_disable();
65 inet_twsk_schedule(tw, timeo);
66 /* Linkage updates.
67 * Note that access to tw after this point is illegal.
68 */
69 inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
70 local_bh_enable();
71 } else {
72 /* Sorry, if we're out of memory, just CLOSE this
73 * socket up. We've got bigger problems than
74 * non-graceful socket closings.
75 */
76 DCCP_WARN("time wait bucket table overflow\n");
77 }
78
79 dccp_done(sk);
80}
81
82struct sock *dccp_create_openreq_child(const struct sock *sk,
83 const struct request_sock *req,
84 const struct sk_buff *skb)
85{
86 /*
87 * Step 3: Process LISTEN state
88 *
89 * (* Generate a new socket and switch to that socket *)
90 * Set S := new socket for this port pair
91 */
92 struct sock *newsk = inet_csk_clone_lock(sk, req, GFP_ATOMIC);
93
94 if (newsk != NULL) {
95 struct dccp_request_sock *dreq = dccp_rsk(req);
96 struct inet_connection_sock *newicsk = inet_csk(newsk);
97 struct dccp_sock *newdp = dccp_sk(newsk);
98
99 newdp->dccps_role = DCCP_ROLE_SERVER;
100 newdp->dccps_hc_rx_ackvec = NULL;
101 newdp->dccps_service_list = NULL;
102 newdp->dccps_service = dreq->dreq_service;
103 newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
104 newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
105 newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
106
107 INIT_LIST_HEAD(&newdp->dccps_featneg);
108 /*
109 * Step 3: Process LISTEN state
110 *
111 * Choose S.ISS (initial seqno) or set from Init Cookies
112 * Initialize S.GAR := S.ISS
113 * Set S.ISR, S.GSR from packet (or Init Cookies)
114 *
115 * Setting AWL/AWH and SWL/SWH happens as part of the feature
116 * activation below, as these windows all depend on the local
117 * and remote Sequence Window feature values (7.5.2).
118 */
119 newdp->dccps_iss = dreq->dreq_iss;
120 newdp->dccps_gss = dreq->dreq_gss;
121 newdp->dccps_gar = newdp->dccps_iss;
122 newdp->dccps_isr = dreq->dreq_isr;
123 newdp->dccps_gsr = dreq->dreq_gsr;
124
125 /*
126 * Activate features: initialise CCIDs, sequence windows etc.
127 */
128 if (dccp_feat_activate_values(newsk, &dreq->dreq_featneg)) {
129 sk_free_unlock_clone(newsk);
130 return NULL;
131 }
132 dccp_init_xmit_timers(newsk);
133
134 __DCCP_INC_STATS(DCCP_MIB_PASSIVEOPENS);
135 }
136 return newsk;
137}
138
139EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
140
141/*
142 * Process an incoming packet for RESPOND sockets represented
143 * as an request_sock.
144 */
145struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
146 struct request_sock *req)
147{
148 struct sock *child = NULL;
149 struct dccp_request_sock *dreq = dccp_rsk(req);
150 bool own_req;
151
152 /* TCP/DCCP listeners became lockless.
153 * DCCP stores complex state in its request_sock, so we need
154 * a protection for them, now this code runs without being protected
155 * by the parent (listener) lock.
156 */
157 spin_lock_bh(&dreq->dreq_lock);
158
159 /* Check for retransmitted REQUEST */
160 if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
161
162 if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_gsr)) {
163 dccp_pr_debug("Retransmitted REQUEST\n");
164 dreq->dreq_gsr = DCCP_SKB_CB(skb)->dccpd_seq;
165 /*
166 * Send another RESPONSE packet
167 * To protect against Request floods, increment retrans
168 * counter (backoff, monitored by dccp_response_timer).
169 */
170 inet_rtx_syn_ack(sk, req);
171 }
172 /* Network Duplicate, discard packet */
173 goto out;
174 }
175
176 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
177
178 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
179 dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
180 goto drop;
181
182 /* Invalid ACK */
183 if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
184 dreq->dreq_iss, dreq->dreq_gss)) {
185 dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
186 "dreq_iss=%llu, dreq_gss=%llu\n",
187 (unsigned long long)
188 DCCP_SKB_CB(skb)->dccpd_ack_seq,
189 (unsigned long long) dreq->dreq_iss,
190 (unsigned long long) dreq->dreq_gss);
191 goto drop;
192 }
193
194 if (dccp_parse_options(sk, dreq, skb))
195 goto drop;
196
197 child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL,
198 req, &own_req);
199 if (child) {
200 child = inet_csk_complete_hashdance(sk, child, req, own_req);
201 goto out;
202 }
203
204 DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
205drop:
206 if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
207 req->rsk_ops->send_reset(sk, skb);
208
209 inet_csk_reqsk_queue_drop(sk, req);
210out:
211 spin_unlock_bh(&dreq->dreq_lock);
212 return child;
213}
214
215EXPORT_SYMBOL_GPL(dccp_check_req);
216
217/*
218 * Queue segment on the new socket if the new socket is active,
219 * otherwise we just shortcircuit this and continue with
220 * the new socket.
221 */
222int dccp_child_process(struct sock *parent, struct sock *child,
223 struct sk_buff *skb)
224{
225 int ret = 0;
226 const int state = child->sk_state;
227
228 if (!sock_owned_by_user(child)) {
229 ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
230 skb->len);
231
232 /* Wakeup parent, send SIGIO */
233 if (state == DCCP_RESPOND && child->sk_state != state)
234 parent->sk_data_ready(parent);
235 } else {
236 /* Alas, it is possible again, because we do lookup
237 * in main socket hash table and lock on listening
238 * socket does not protect us more.
239 */
240 __sk_add_backlog(child, skb);
241 }
242
243 bh_unlock_sock(child);
244 sock_put(child);
245 return ret;
246}
247
248EXPORT_SYMBOL_GPL(dccp_child_process);
249
250void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
251 struct request_sock *rsk)
252{
253 DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
254}
255
256EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
257
258int dccp_reqsk_init(struct request_sock *req,
259 struct dccp_sock const *dp, struct sk_buff const *skb)
260{
261 struct dccp_request_sock *dreq = dccp_rsk(req);
262
263 spin_lock_init(&dreq->dreq_lock);
264 inet_rsk(req)->ir_rmt_port = dccp_hdr(skb)->dccph_sport;
265 inet_rsk(req)->ir_num = ntohs(dccp_hdr(skb)->dccph_dport);
266 inet_rsk(req)->acked = 0;
267 dreq->dreq_timestamp_echo = 0;
268
269 /* inherit feature negotiation options from listening socket */
270 return dccp_feat_clone_list(&dp->dccps_featneg, &dreq->dreq_featneg);
271}
272
273EXPORT_SYMBOL_GPL(dccp_reqsk_init);